LM2594: Inrush current

Takayuki Ishimori

Part Number: LM2594

Is it possible for the current limiting function to operate in response to the inrush current?
If so, what kind of load can prevent the current limiting function from working?
Is it possible to specify by the input capacity of the load?

over 4 years ago

0 Xiaoying Lu over 4 years ago

TI__Expert 4280 points

Hi Takayuki,

LM2594 is with peak current limit feature and the typical current limit value is 0.8A. You can calculate the inrush current giving the condition of output voltage and capacitance to see it it will trigger the peak current limit.

If it is so, you can also consider the delayed start-up function in datasheet section 8.3.1, where the input capacitor is allowed to charge up to a higher voltage
before the switcher begins operating. A portion of the high input current needed for start-up is now supplied by the input capacitor .

Regards,

Xiaoying

0 Xiaoying Lu over 4 years ago

TI__Expert 4280 points

Hi Takayuki,

If you have no more questions, pls help click "resolved" button for us to close this thread.

Xiaoying

0 Takayuki Ishimori over 4 years ago in reply to Xiaoying Lu

Prodigy 10 points

What are the conditions under which current limiting works?
Isn't there a lower limit of the current threshold and a duration condition?

0 Xiaoying Lu over 4 years ago in reply to Takayuki Ishimori

TI__Expert 4280 points

Hi Takayuki,

The current limit is fixed and you can find the typical value, min value and max value in the datasheet (temperature variation will influence the sense and limit results).

But we don't have any mechanism to change the current limit under a duration condition.

Regards,

Xiaoying

+1 Xiaoying Lu over 4 years ago

TI__Expert 4280 points

Hi Takayuki,

If you have no more questions, pls help click "resolved" button for us to close this thread.

Xiaoying

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LM2594: Inrush current